An animal model of respiratory hypersensitivity to industrial chemicals is being developed using guinea pigs. Repeated exposure of animals to antigen aerosols, containing hapten-protein conjugates, results in pulmonary sensitization to the haptenic portion of the antigens. This procedure provides a general method for inducing sensitivity to small chemical determinants. Proposed research will be directed toward elucidation of the role of the carrier portion of the antigens in respiraory sensitization. Both natural and synthetic polymers, covering a broad range of molecular weights, will be employed as carrier molecules. Concurrently, attempts will be made to induce pulmonary hypersensitization by repeated exposure of animals to haptens alone. If successful, chemicals with known allergenic abilities will be used as sensitizing haptens. In this way the allergenic abilities of various industrial chemicals can be evaluated in the guinea pig and compared to their reported potencies in man. This comparison will enable assessment of the value of the guinea pig model for pulmonary sensitization. A further aspect of the research will involve the use of hapten-protein conjugates to detect antibodies in sera from TDI-sensitive workers. Such conjugates have been shown to induce tolyl sensitivity in guinea pigs.